function animate(obj, target, func) {
    clearInterval(obj.timer);
    obj.timer = setInterval(function () {

        var step = (target - obj.offsetLeft) / 10;
        step = step > 0 ? Math.ceil(step) : Math.floor(step);

        if(obj.offsetLeft == target){
            clearInterval(obj.timer);

            if(func){
                func();
            }

        }else{
            obj.style.left = obj.offsetLeft + step + 'px';
        }
    },30);
}